This invention relates to medical ultrasound imaging, and more particularly, to an endo-luminal ultrasonic instrument and method for its use.
One type of endo-luminal ultrasonic instrument has a single rotating ultrasonic transducer element or ultrasonic reflector at the end of a flexible stationary catheter. The transducer element or reflector rotates with respect to the catheter to perform a B-scan in a plane perpendicular to the axis of the catheter.
Another type of endo-luminal ultrasonic instrument has a plurality of stationary ultrasonic transducer elements arranged around the circumference of the end of a flexible stationary catheter. The transducer elements are sequentially actuated in groups to perform a B-scan in a single plane perpendicular to the axis of the catheter. This type of instrument is disclosed in U.S. Pat. No. 3,938,505 to Bom. Being confined to a single plane perpendicular to the catheter axis, both of the described types of instruments do not exhibit good longitudinal, i.e., axial resolution.
Herres U.S. Pat. No. 5,070,879 discloses a hand-held transrectal ultrasonic imaging instrument incorporated in a rigid longitudinal housing. Inside the housing, an array of ultrasonic transducer elements is axially arranged for oscillation about the longitudinal axis.